In this Letter, we innovatively present general analytical expressions for arbitrary n-step phase-shifting Fourier single-pixel imaging (FSI). We also design experiments capable of implementing arbitrary n-step phase-shifting FSI, and compare the experimental results, including image quality, for 3-6 steps phase-shifting cases without loss of generality. These results suggest that, compared to the 4-step method, these FSI approaches with a higher number of steps exhibit enhanced robustness against noise while ensuring no increase in data acquisition time. These approaches provide us more strategies to perform FSI for different steps, which could offer guidance in balancing the tradeoff between image quality and the number of steps encountered in the application of FSI.

The hologram, which is formed by phases coupled through cascade devices for secret information sharing, still carries a cracking risk. We propose a liquid crystal planar doublet as the information carrier, and new holograms generated by the new coupled phases when the relative displacements of the different liquid crystal layers change. The designed geometrical phases are generated by an optimized iterative restoration algorithm, and each holographic image formed by these phases is readable. This scheme achieves an increase in the capacity of the stored secret information and provides more misdirection, which is expected to have potential value in optical steganography and storage.

The existing single crystals slicing techniques result in significant material wastage, and the heightened cost of premium-quality thin disk crystals. Here we first report an approach for vertical slicing of large-size single crystal gain materials by ultrafast laser. By employing aberration correction techniques, the optimization of the optical field distribution within the high-refractive-index crystal enables the achievement of a continuous laser-modified layer with a thickness of less than 10 μm, oriented perpendicular to the direction of the laser direction. The compressed focal spot facilitated crack initiation, enabling propagation under external forces, ultimately achieving the successful slicing of a Ф12 mm crystal. The surface roughness of the crystal thin disk is less than 2.5 μm. The results illustrate the potential of low loss slicing strategy for single crystals fabrication and pave the way for the future development of thin disk lasers.

Resolving power describes the ability of an imaging system to resolve the objects details and is important for evaluating the imaging performance during optimization with various of technologies. The information-theoretic viewpoint based on communication theory or statistical inference theory can provide objective and operational measures on resolving power. These approaches can be further developed by combining with the quantum statistical inference theory for optimizing the resolving power over measurements and analyze its quantum limits. The aim of this review is to discuss and analyze the recent development in this branch of quantum imaging.

Optical frequency comb has attracted considerable interest due to its diverse applications in optical atomic clock, ultra-low-noise microwave generation, dual-comb spectroscopy, and optical communications. The merits of large frequency spacing, high integration, and low power consumption have shown that microresonator-based Kerr optical frequency combs will become mainstream in the future. Two methods of pump frequency tuning and self-injection locking were used to obtain Kerr combs in the same silicon nitride microresonators with free spectral ranges of 50 GHz and 100 GHz. Single soliton combs are realized with both methods. Simplicity, pump power, spectrum bandwidth, conversion efficiency, and linewidth are compared and analyzed. Our results show that the advantages of pump frequency tuning are a wider spectrum and higher soliton power while the advantages of self-injection locking are simplicity, compactness, low cost, significant linewidth narrowing, and high conversion efficiency.

Recently, the Fano resonance has played an increasingly important role in improving the color performances of structural colors. In this study, we further elucidated the asymmetric spectral shape generated by Fano resonance from a phase perspective and explored four distinct continuum state structures. By integrating the proposed cavity-like structure with a Metal-Insulator-Metal discrete state, multilayered thin-film structural colors with minimal background reflection, as low as 8%, were successfully achieved. The reflection peak of this structure exhibits a bandwidth of approximately 50 nm and reaches up to 80%, indicating heightened saturation and color brightness. Moreover, by adjusting the thickness, we effortlessly obtained a broader color gamut compared to Adobe RGB (45.2%), covering 56.7% of the CIE color space. Even adjusting a single layer can achieve a color gamut of 47.1%. In experiments, by deliberately choosing low oxygen-dependent materials, excellent RGB colors with high brightness and in high consistency with simulation results were successfully achieved. Therefore, the scheme’s simple process for structural colors creation, along with its excellent color performance and the ability to effectively replicate simulation characteristics makes it highly valuable in fields like anti-counterfeiting, decoration, display devices and solar cell panels.

The metabolic process of chiral drugs plays a significant role in clinic and research of drugs. Here, we experimentally demonstrate by all-optical means that the chiral molecules can be quickly discriminated and monitored with the ultrahigh-order modes excited in a metal cladding optofluidic chip, achieving over 5 times sensitivity with low-dosage sample. We show that the varying concentration of the chiral drugs can be monitored both in cell and animal experiments, presenting significant difference between chiral enantiomers at the optimal function time and the effect of the reaction. To our knowledge, this approach provides a new way to achieve important chiral discrimination for the pharmacokinetics and the pharmacodynamics and may present opportunities in indicating the health status of humans.

In the field of long-wave infrared (LWIR) thermal imaging, vital for applications such as military surveillance and medical diagnostics, metalenses show immense potential for compact, lightweight, and low-power optical systems. However, to date, the development of LWIR broadband achromatic metalenses with dynamic tunable focus, which are suitable for both coaxial and off-axis applications, remains a largely unexplored area. Herein, we have developed an extensive database of broadband achromatic all-As2Se3 microstructure units for the LWIR range. Utilizing this database with the Particle Swarm Optimization (PSO) algorithm, we have designed and demonstrated LWIR broadband achromatic metalenses capable of coaxial and off-axis focusing with three dynamic tunable states. This research may have potential applications for the design of compact, high-performance optical devices, including those with extreme depth-of-field and wide-angle imaging capabilities.

Lasers from ¹I₆ to ³F₄ transitions were first demonstrated in a Pr³⁺:YLF crystal by inserting a birefringent filter. Output powers up to 2.44 W, 2.10 W, 2.01 W and 2.42 W were obtained at 691.7 nm, 701.4 nm, 705.0 nm and 708.7 nm. Their slope efficiencies were 19.8%, 16.5%, 15.8% and 19.4%, respectively. The Mx² and My² factors were measured to be 2.29 and 2.03 at 691.7 nm, 2.23 and 1.86 at 701.4 nm, 2.31 and 2.08 at 705.0 nm, and 2.41 and 2.04 at 708.7 nm, with corresponding power fluctuations of less than 5.3%, 5.6%, 5.8%, and 2.9%.

In this work, we proposed and experimentally demonstrated a novel probabilistic shaping (PS) 64QAM-OFDM with low-density parity-check (LDPC)-coded modulation in a W-band RoF system using envelope detection. The proposed PS scheme has the advantages of no complex multiplication and division operations and low hardware implementation complexity. In our experiments, the TS-BWDM-based PS-64QAM DMT signals with a rate of 28.3-Gb/s transmission over 4-m wireless + 45-km SSMF transmission can be achieved. The system performance is investigated under one LDPC code rates (3/4) and two PS parameter values (k=3 and 9). The experimental results show that the receiver power sensitivity and the system fiber nonlinear effect tolerance can be significantly improved compared with uniformly-distributed signals.